Magnetically induced friction damping based on magnetoactive elastomers — A proof of concept

Abstract

In this work we present a new concept for friction damping which is based on the permanent magnetization and the flexibility of magnetoactive elastomers (MAE). The concept is called “magnetofriction” and is studied on a sandwich structure in the present work. The assembled structure consists of a MAE core and ferromagnetic skins. Due to the magnetization of the MAE, the skins are attracted to the core and the sandwich is assembled without the need of glue or other means of fixation. The magnetic forces generate the normal loading in the contact interfaces between skins and core while a tangential loading is induced by forced vibrations applied to the sandwich beam. Random and harmonic vibration tests reveal the nonlinear dynamic behavior of the sandwich structure and highlight the damping capacity of magnetofriction. The harmonic balance method is used on a nonlinear dynamic model of the system to identify the parameters related to the resonance frequency and damping ratio. The results obtained from the identification state damping ratios up to 9% under harmonic excitation, which is remarkable for friction damping. In addition, a Finite Element-based model of the structure is implemented to study the local contact states in the sandwich. Multi-physical simulations are performed to analyze the magnetic and mechanical loading in the contact interface. The local results are used to evaluate the overall contact states in the interfaces which determine the absence or presence of friction damping. The simulations show that the vibration amplitude changes the contact state.